INTRODUCTION 9 
any extended а of the sea and retaining their vitality seems 
very remote. 
A departure from the customary classification’ is made in the 
treatment of the Anthocerotales. The common ly accepted arrange- 
ment recognizes two classes—the Hepaticae and the Musci—in the 
phylum or subkingdom BRYOPHYTA, though by some writers the 
Sphagnaceae are taken out from the Musci and made a separate 
class. Under the class Hepaticae are ordinarily recognized the 
three orders. Marchantiales, Jungermanniales, and Anthocerotales. 
The last-named group differs from the Hepaticae proper in very 
_ important characters. and we think these differences are best em- 
phasized by raising the Anthocerotales to the rank of a class (under 
the name ANTHOCEROTES), coordinate with the Hepaticae, restrict- 
ing this last term to the Marchantiales and Jungermanniales. This 
idea is not wholly a new one. Students of plant morphology, 
among whom : Professor D. Н. Campbell may be especially 
mentioned, have been approaching this view for several years, 
апа this position was definitely taken by Mons. Г. A. Gayet* 
in 1807 as a result of investigations on the archegonium 
alone, though the class was not named and defined by him in the 
1ormal systematic way. The peculiarities of the ANTHOCEROTES, 
briefly enumerated, are: (1) A single large chloroplast to each 
cell, instead of several smaller chloroplasts as in the assimilative 
tissues of the Hepaticae. proper. Chlorophyll bodies like Шезе-- 
solitary in the cell—are known to occur elsewhere only in certain 
green algae and in certain tissues of Se/aginella.t (2) The an- 
theridia arise within the thallus—are endogenous in origin—and 
the walls of the immersed archegonia are confluent with the 
adjacent tissues. (3) The presence of meristematic tissue in the 
capsule near its base, by the activity of which the capsule has a 
long continued growth, ripening spores toward its apex while form- 
ing new spore-mother-cells below. (4) The presence, in probably 
all cases, of a columella around which the archesporium is formed. 
(5) The presence, in many cases, of stomata on the capsule, with 
accompanying assimilative tissue. These five characters are pecu- 
liar to the Anthocerotes as distinguished from the Hepaticae proper 
Ann. Sci. Nat. Bot. VIII. 3: 243, 244. 1897. 
ro D. H. The Structure and Development of Mosses and Ferns, 115. 1895. 
